Bicycle Rim for Tubeless Tire

ABSTRACT

Bicycle rims that allow tires to be more easily mounted in a tubeless configuration are disclosed. More specifically, a bicycle rim may control the two beads of the tire with separate bead channels for each bead and a center bridge extending between the two bead channels.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims a benefit of priorityunder 35 U.S.C. 120 of the filing date of U.S. patent application Ser.No. 14/485,224 filed Sep. 12, 2014 entitled “BICYCLE RIM FOR TUBELESSTIRE” claims the benefit of priority under 35 U.S.C. 119(e) to U.S.Provisional Patent Application 61/880,052 filed Sep. 19, 2013, entitled“BICYCLE RIM FOR TUBELESS TIRE” by Christopher Andrew Edin and StevenArthur Hed, and U.S. Provisional Patent Application No. 61/900,833 filedNov. 6, 2013, entitled “BICYCLE RIM FOR TUBELESS TIRE” by Steven ArthurHed, both of which are hereby fully incorporated by reference herein.

TECHNICAL FIELD

This disclosure relates generally to bicycle wheel rims. Specifically,this disclosure also relates to bicycle wheel rims shaped to allow atire to be mounted and utilized in a tubeless configuration. Moreparticularly, this disclosure also relates to bicycle wheel rims shapedto allow larger width tires to be mounted and utilized in a tubelessconfiguration.

BACKGROUND

Standard tires with tubes have certain advantages. For example, tireswith tubes are easier to repair as all that is required is thereplacement of a punctured tube; may have the ability to maintainpressure for long periods and usually do not require special adaptationof the rim for sealing. However, utilizing tires with tubes has a numberof disadvantages as well. One disadvantage is that such tires may sufferfrom “pinch flats” in which the tube becomes momentarily pinched betweenthe tire casing and the rim, tearing the tube. This problem isparticularly acute for mountain bikes which tend to run tires at lowerpressure and over rougher terrain. Another disadvantage is their weight.Tubeless bicycle tires do not suffer pinch flats and can be lighterbecause of the absence of the tube itself, however, the tubelessarrangement requires a sealed rim, a bead to rim seal and an airimpermeable tire. Thus, the configuration of tubeless tires has provedproblematic in certain applications.

One example of such an application is when a tubeless tire is used on abicycle that takes wider tires. This type of bicycle is commonlyreferred to as a “fat bike”. The tire size for these bikes is normallythree to five inches wide. Correspondingly, the wheel rims (or just“rims”) used for this size tire tend to be between 50 mm to 100 mm wide(and in many cases between 65 mm and 85 mm), and the diameter is mostlythe 26 inch designation but there are also 29 inch fat bikes and in thefuture the expectation is that there will be even more sizes such as27.5 inch.

In a conventional tubeless tire setup for bicycles, there is a centerchannel in the rim that the tire beads rest in an uninflated state.During inflation of the tire when a sufficient pressure is reachedwithin the tire bead travels (or “pops”) onto a shelf formed in the rimthereby sealing the system, holding the tire in place and allowing it toretain a desired pressure. These conventional designs are, however,inadequate for tires of larger width or in certain cases when trying toinflate the tire with a manual air pump. In the main, this is the casebecause as the width of the rim and the tire increases, the area betweenthe beads of the tire as it rests on the center channel commensuratelyincreases.

Having a center channel that holds the beads, but that is alsosufficiently tight to allow a sufficient pressure to be established suchthat the tubeless tire “pops” onto the rim ledges is difficult In part,this is because there is a significant variation in the actual diameterof tires from different manufacturers. For example, a 26 inch tire fromone manufacturer may be several millimeters larger than a 26 inch tirefrom another manufacturer. Moreover, there can be significant diameterdifferences within a single tire due to manufacturing tolerances (e.g.,because the bead is warped). Therefore it can be difficult to produce atubeless rim that works reliably.

Additionally, such a center channel may be problematic because if thereis a deep well in the center of the rim it is difficult to get the beadsto “behave” properly. Beads may flex or otherwise move in such a mannerthat creates a gap between at least one of the beads and the rim so thatair escapes and a threshold pressure within the tire that would allowthe tire to inflate in a “tubeless” manner (e.g., to get the beads to“pop” onto a retaining shelf) cannot be established. Such gaps areparticularly likely to occur when the beads pop over a sharp transitionto a retaining shelf.

To attempt to address some of these problems, certain tubeless rims havebeen designed for user with a particular bead size and shape. Rims ofthis type are, however, incompatible with any other type of tubelesstire that does adhere to such a bead size and shape.

What is desired then, is a bicycle wheel rim shaped to allow easierinflation of tires when used in a tubeless configuration and that mayalso be used with a wide variety of tires.

SUMMARY OF THE DISCLOSURE

To that end, embodiments of a bicycle rim that address the problem ofmaking large sized mountain bike tires and other fat bike tires work ina tubeless way are disclosed herein. More specifically, embodimentsdescribed herein may control the two beads of the tire with separatebead channels for each bead. This provides easy installation of the tireonto the rim and allows the tire to inflate tubelessly. Holding thebeads closely to the bead seat of the rim and controlling the bead seatsproperly allows for the beads to pop into place with less air volume.This is because less air is escaping from the system. Furthermore thissolution allows the rim to be made of a single wall, and with or withoutchambers, which simplifies construction and manufacturing of the rimparticularly when constructing the rim in carbon fiber.

Embodiments of such a bicycle rim adapted to seat both tubeless and tubetires may include an annular support portion forming a continuous ring.This support portion may have a tapered bead channel disposed to oneside of a centerline of the support portion and another tapered beadchannel disposed to the other side of the centerline. Both of thesetapered channels may have the same bead channel diameter, which may, inone embodiment, be configured to be substantially the diameter of thebeads of an appropriately sized tire in an uninflated state. Each of thebead channels may have a bead channel outer sidewall sloped such that aradially outer end of the bead channel outer sidewall is laterallyoutward of a radially inner end of the bead channel outer sidewall and abead channel inner sidewall. The support portion may also include twobead seat portions disposed across the centerline and laterally outwardof the bead channels. These bead seat portions may have a bead seatdiameter that is greater than the bead channel diameter and beconfigured to accommodate the beads of an appropriately sized tire in aninflated state. The support portion may also include two rim ledgesextending from a respective bead channel outer sidewall to a respectivebead seat portion and a center bridge extending between the innersidewalls of each bead channel bead. The diameter at a first lateral endand a second lateral end of the center bridge may be greater than thebead seat channel diameter, bead seat diameter and diameters of thefirst rim ledge and second rim ledge. The bicycle rim also includes rimsidewalls disposed across the centerline and extending radially outwardfrom the support portion at each lateral end of the support portion.

Such a rim may, in certain embodiments, be created by affixing aseparate annular rim strip to a bicycle rim. In particular, in someembodiments, a ring of material may be placed inside conventionallyshaped tubeless rims. Such embodiments may be shaped to be press fitinto the center channel or otherwise held in place such as by a zip tieor the like, to form a friction fitting with the one or more walls ofthe center channel of the conventionally shaped tubeless rim such thatthe combination of the tubeless rim and the ring form a rim shapedaccording to embodiments as disclosed herein.

Thus, in certain embodiments mounting a tire in a tubeless configurationon such a rim may comprise placing the rim between the beads of the tirebeads, placing a tire bead in the one of the bead channels; placing theother tire bead in the other bead channel and inflating the tire so thatthe beads transition from the bead channels to the bead seats. To aid inthe inflation of the tire, in certain embodiments, a mechanical seal maybe placed either one of, or both, the bead channels prior to, orsubsequently to, placing the tire beads in the bead channels. Such amechanical seal may be, for example, an elastic rim, or rim tape whichmay be used in preparing the bicycle rim for the mounting of a tire(e.g., used for sealing spokes or the like).

Embodiments as disclosed herein may therefore provide a number ofadvantages. Namely, embodiments of a rim shaped accordingly may allowthe use of wider tires in a tubeless configuration. The rims themselvesmay thus be made wider and the tires used may be wider and achieve asubstantial weight reduction relative to operation of an equivalentlysized tire in a configuration utilizing a tube. Additionally, asembodiments may be of a single wall and without chambers, ease ofconstruction in various materials may be achieved.

Embodiments may also have the advantage of being able to accommodate forvariations in tire sizes that exist between manufacturers and even formanufacturing variations within tires from the same manufacturer thatare ostensibly of the same diameter. Additionally, they may also havethe advantage of being able to accommodate beads of different shapes andsizes from different manufacturers and account for warping of thesebeads that occur, for example, during storage or transport of suchtires.

For example, while tires from two different manufacturers may both bespecified for use with a 29 inch rim, the tire from one manufacturer mayfit “loosely” while the 29 inch tire from the second manufacturer may be“tight”. In other words, there may be variations between the radialdistances between the beads of two of the same sized tires betweendifferent manufacturers. Additionally, even different examples of thesame tire coming from the same manufacturer may have different diametersbecause of, for example, manufacturing tolerances or the like. Certainembodiments as disclosed herein, at least because of the shape of thebead channels of these embodiments, may more easily accommodate thevariations of tire diameter between manufacturers and tires and accountfor differentiation within the beads of any given tire itself (e.g.,caused by warping of the bead) and therefore allow the use of a greatervariety of tires in a tubeless configuration.

These, and other, aspects of the invention will be better appreciatedand understood when considered in conjunction with the followingdescription and the accompanying drawings. The following description,while indicating various embodiments of the invention and numerousspecific details thereof, is given by way of illustration and not oflimitation. Many substitutions, modifications, additions orrearrangements may be made within the scope of the invention, and theinvention includes all such substitutions, modifications, additions orrearrangements.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings accompanying and forming part of this specification areincluded to depict certain aspects of the disclosure. A clearerimpression of the disclosure will become more readily apparent byreferring to the exemplary, and therefore non-limiting, embodimentsillustrated in the drawings. Wherever possible, the same referencenumbers will be used throughout the drawings to refer to the same orlike features (elements). The drawings are not necessarily drawn toscale.

FIG. 1A illustrates a bicycle rim with a tire in a first state and FIG.1B illustrates the bicycle rim with a tire in a second state.

FIG. 2 is a diagrammatic representation of one embodiment of a bicyclerim.

FIG. 3 is a diagrammatic representation of one embodiment of a bicyclerim.

FIG. 4 is a diagrammatic representation of one embodiment of a bicyclerim.

FIG. 5A is a diagrammatic representation of one embodiment of a bicyclerim with a chamber and FIG. 5B is a diagrammatic representation ofanother embodiment of a rim with a chamber.

FIG. 6A is a diagrammatic representation of a rim strip, FIG. 6B is adiagrammatic representation of a rim with a rim strip installed, FIG. 6Cis a diagrammatic representation of another embodiment of a rim stripand 6D is a diagrammatic representation of another embodiment of a rimstrip.

FIG. 7A is a diagrammatic representation of a bicycle rim with a tire ina first state, FIG. 7B is a diagrammatic representation of a portion ofan embodiment of a bicycle rim and FIG. 7C is a diagrammaticrepresentation of a bicycle rim with a tire in a second state.

DETAILED DESCRIPTION

Rims for tubeless tires and the various features and advantageousdetails thereof are explained more fully with reference to thenonlimiting embodiments that are illustrated in the accompanyingdrawings and detailed in the following description. Descriptions ofwell-known starting materials, processing techniques, components andequipment are omitted so as not to unnecessarily obscure the inventionin detail. It should be understood, however, that the detaileddescription and the specific examples, while indicating preferredembodiments, are given by way of illustration only and not by way oflimitation. Various substitutions, modifications, additions and/orrearrangements within the spirit and/or scope of the underlying conceptwill become apparent to those skilled in the art from this disclosure.

Reference is now made in detail to the exemplary embodiments of thedisclosure, examples of which are illustrated in the accompanyingdrawings. Wherever possible, like numerals will be used throughout thedrawings to refer to like and corresponding parts (elements) of thevarious drawings. Any examples or illustrations given herein are not tobe regarded in any way as restrictions on, limits to, or expressdefinitions of, any term or terms with which they are utilized. Instead,these examples or illustrations are to be regarded as being describedwith respect to one particular embodiment and as illustrative only.

Those of ordinary skill in the art will appreciate that any term orterms with which these examples or illustrations are utilized willencompass other embodiments which may or may not be given therewith orelsewhere in the specification and all such embodiments are intended tobe included within the scope of that term or terms. Language designatingsuch nonlimiting examples and illustrations includes, but is not limitedto: “for example,” “for instance,” “e.g.,” “in one embodiment.”

For example, while embodiments of rims as disclosed herein will bediscussed with respect to use of these rims with tires in a tubelessconfiguration, it will be noted that these embodiments may be utilizedequally well in configurations that include a tube. Furthermore, whileillustrative examples have been provided in conjunction with embodimentsdesigned for use with fat bikes, embodiments may also be applied to non“fat bike” sized rim/tires and can be used for more conventionalmountain bike as well as road bike rim/tire sizes. In the same vein,while specific measurements (e.g., widths, lengths, heights, radiuses,angles, etc.) have been given in conjunction with various embodiments itshould be understood that these measurements are given by way of exampleand rims with other measurements are fully contemplated by theembodiments described herein.

As is well known in the art, a bicycle wheel (either a front or rearwheel) includes a rim connected to a central hub via a set of spokes ora disk. The spokes may be of a suitable type, straight or bent, andtheir arrangement can be either radial or crisscrossed. The rim may bemade from a section or length of steel, light alloy, aluminum, carbonfiber or other material curved to form an annular support member andhaving two ends that are assembled together by welding or anotherfastening technique, so as to form a continuous ring by joining the twoends. In some case, the rim has openings for joining the spokes to therim while in other cases the spokes may be formed integrally with therim (e.g., as in a “mag” wheel).

The outer surface of the rim therefore comprises a surface upon whichtires may be mounted. The shape of this mounting surface maysignificantly influence the ease of tire mounting or inflation. Inparticular, the height, shape and thickness of this mounting surface maycontribute to overall rim weight, strength, tire stability, air leakage,and other considerations appreciated by those skilled in the art.Several issues to be considered with respect to the mounting surfacethus include the ability to uniformly position the beads of a tire onthe mounting surface prior to inflation, the ease of tire inflation(particularly, for example, with a manual pump), the interchangeable useof tubes and/or tubeless tires, and other considerations recognized inthe art.

Before discussing certain embodiments as presented herein in moredetail, it may be helpful to an understanding of those embodiments tofirst discuss a conventional tubeless tire setup for bicycles. Turningfirst then to FIGS. 1A and 1B, a cross section of a conventional rimadapted to mount tires in a tubeless configuration is illustrated. Rim100 includes an inner wall 110 joined at each end to a tire mountingsurface 120 such that a chamber 130 is formed between the tire mountingsurface 120 and the inner wall 110. The tire mounting surface 120includes a center channel 140. When an uninflated tire 160 is placed onthe rim 100 the beads 150 of the tire 160 rest in this center channel140. As the tire 160 is inflated, and a threshold pressure is reachedwithin the tire 160, the tire 160 expands and the beads 150 of the tire160 travel along the tire mounting surface 120 in a direction away fromthe centerline (or normal axis) of the rim 100 onto shelf 180 of tiremounting surface 120. The shelf 180, in combination with the sidewalls170 disposed at the lateral peripheries of the tire mounting surface120, hold the beads 150 of the tire 160 in place and, as such, seal thesystem comprised of the rim and the tire.

Conventionally, sidewalls 170 also include a “hook” or projection or lipthat curves toward the centerline of the rim to assist in capturing andholding the beads 150 in place. This configuration may present an issueif the tire bottoms out. More specifically, fat bike tires are often runat low pressure which causes the tire to bottom out when the wheel hitsan obstruction, lands from a jump, etc. Bottoming out in a configurationsuch as depicted in FIGS. 1A and 1B places force on the ends of the rimsidewalls 170, resulting in a high moment about the base of the sidewall(e.g., as the sidewalls cantilever relative to their base) andpotentially highly localized stress at the bottom corners of the rimsidewalls 170. In rims made of certain material, such as carbon fiber,this can cause cracking.

Rims such as that depicted in FIGS. 1A and 1B may therefore be suitablefor skinnier tires where the rim is typically less than 30 mm wide. Asdiscussed above, however, certain bikes, such as fat bikes, may utilizerims and tires of significantly greater width. As such, rims like thosedepicted in FIGS. 1A and 1B may be unsuitable for these types ofapplications, among others.

Attention is thus directed to embodiments of bicycle rims presentedherein. Among other advantages, embodiments as described herein addressthe problem of making large sized mountain bike tires and other fat biketires work in a tubeless configuration. To that end, embodiments of abicycle rim may include a mounting surface that includes a separate beadchannel for each bead of the tire. These bead channels are shaped toallow easy installation of the tire onto the rim without a tube and tocontrol the beads of the tire (e.g., the movement of the beads of thetire) during inflation such that the beads of the tire (or portionsthereof) may maintain greater contact with the mounting surface of therim during the inflation process. Controlling the beads of the tire inthis manner allows the beads of the tire to “pop” or move into a beadseat with less air volume, as less air is escaping from the system.Furthermore, embodiments as described allow a rim to be made without anychambers or inner walls, which simplifies construction and manufacturingof the rim, particularly when constructing the rim in carbon fiber

FIG. 2 illustrates one embodiment of a rim 200 having spaced tire beadchannels 210 that receive the beads of tire 220 prior to inflation. Thebead channels 210 may be tapered and formed through the cooperation ofan inner sidewall 212 and an outer sidewall 214, with the outer sidewall214 of the bead channel 210 transitioning to a rim ledge 216. The ledge216 includes a bead seat portion 218 at the junction of the rim sidewall222 and the ledge 216.

In one embodiment, the outer sidewalls 214 of bead channels 210 thattransition to the ledge 216 may be relatively shallow. Furthermore,according to one embodiment, the inner sidewall 212 of the bead channels210 may have a higher angle from the rim's axis of rotation (i.e., theradial axis). The ledge 216 may be angled as well. For example the ledge216 may have a negative angle relative to a reference line parallel tothe rim's axis of rotation (e.g., be greater than 90 degrees from thenormal axis). Embodiments such as these as will be explained in moredetail at a later point herein. The taper of bead channels 210 allowsbeads of various sizes and shapes to be accommodated and create a sealagainst outer walls 214.

When a bead travels over a sharp transition between a channel and rimshelf, the bead tends to pop away from the rim allowing air to escapeand inhibiting inflation. According to one embodiment then, the rim 200may also be shaped to avoid or reduce the number of sharp corners atwhich the bead of a tire can separate from the rim 200 and thus promotecontact between the tire bead and rim 200. In such embodimentstherefore, the transition from the outer sidewall 214 of the beadchannel to the tire shelf 216 may be an outside curve. The radius ofthese curves may be chosen to ease the formation or manufacture of therim 200 in a particular material. For example, the radius of thesecurves may be chosen such that they may be more easily molded orotherwise formed in carbon fiber.

Embodiments of rim 200 advantageously do not require an inwardlyprojecting lip or hook at the end part of the upper the rim sidewall. Ascan be seen, rim sidewall 222 may comprise an outside curve thatcontacts the outside of the tire casing when the tire is in an inflatedstate. The curvature of sidewall 222 can help retain the tire bead. Thesidewall, in this embodiment, thus is not curved back in at the end (thetip of the rim sidewall is angled slightly out). Force from bottomingout will be distributed along the curved sidewall 222 and to a curvedtransition from the sidewall 222 to the ledge 216. This creates a betterdistribution of internal stress, thereby reducing the likelihood ofcracking in rim 200 (e.g., a rim composed of carbon fiber).

Embodiments such as those depicted may also be a single wall of auniform or near uniform thickness. A uniform thickness can make the rimeasier to produce using certain materials, including carbon fiber. Inother embodiments however, the rim may have varying thicknesses indifferent portions. These varying thicknesses may be helpful tostrengthen the rim in certain areas and may be used when the rim isformed of certain metals, such as aluminum. Embodiments may also beoptimized for manufacture in carbon fiber or other material. Forexample, transitions may be curved (e.g., the bottom of bead channels210 may be an inner curve, the transition from outer wall 214 to ledge216 may be an outer curve, etc.) with radiuses selected to promote cleanmolding in carbon fiber.

Embodiments may be better explained with reference to FIG. 3 whichdepicts a cross-sectional view radially opposite portions of a bicyclerim adapted to seat a tire in a tubeless configuration. The rim 300 iscomprised of an annular support portion forming a continuous ring abouta radial axis. Thus, in FIG. 3, cross sections 300 a and 300 b are crosssections of rim 300 opposed across the radial axis of rim 300.

The rim 300 may be a single wall having an outer surface (i.e., thesurface nearest to a tire when a tire is mounted on rim 300) and innersurface. The single wall can define an annular main mounting or supportportion 302 and rim sidewalls 380 that are radially outward at thelateral ends of the support portion 302. Such a rim may come in variouswidths depending on the width of tire accommodated. Tapered beadchannels 310 are disposed across the centerline (i.e., the normal axis)of the support portion 302. Each of the bead channels 310 may be of adiameter configured to accept the bead of a tire in an uninflated state.This bead channel diameter 350 is the distance between radially oppositeportions of the same bead channel 310 of rim 300. Each of the beadchannels 310 are formed from bead channel outer sidewall 312 and beadchannel inner sidewall 318. In some embodiments, bead channel 310includes a continuous inner curve between bead channel inner sidewall318 and the bead channel outer sidewall 312. This curve may have aradius of between about 2 and 4 mm on the outer surface of the rim 300in some embodiments, though other radii may be used.

This outer sidewall 312 may be sloped or curved (collectively referredto using “slope” or “sloped” herein) such that a laterally outward end314 of the outer sidewall 312 is radially outward of the laterallyinward end 316 of the outer sidewall 312. In other words, the laterallyoutward end 314 of the outer sidewall 312 may be farther from the radialaxis of the rim 300 than the laterally inward end 316. In oneembodiment, the slope of outer sidewalls 312 may be relatively shallow,for example less than 60 degrees and in some cases less than 45 degreesfrom a reference line parallel to the rim's radial axis (e.g., greaterthan 30 degrees from the normal axis). In other embodiments, the outersidewalls 312 may have a higher angle and in some embodiments may besubstantially parallel to the normal axis. For example, in certainembodiments the angle between the outer sidewall 312 and a referenceline parallel to the normal axis may be between 35 and 50 degrees.

Rim 300 also includes bead seat portions 322 that are disposed laterallyoutward of the bead channel 310 and, in particular, may be disposedlaterally outward from the laterally outward end 314 of the bead channel310. Rim ledge 326 extends from the laterally outward end 314 of outersidewall 312 of bead channel 310 to bead seat portion 322. Thetransition between the laterally outward end 314 of outer sidewall 312and rim ledge 326 may be curved outwardly at a radius configured toprevent a gap from forming between the beads of a tire as the bead ofthe tire moves from the outer sidewall 312 of the rim 300 to the rimledge 326 during inflation of the tire. For example, the radius of thistransition may be between 1 and 3 mm at the outer surface of the rim300, though other radii may be used.

Each of the bead seat portions 322 may be of a diameter configured toaccept the bead of a tire in an inflated state. This bead seat diameter328 is the distance between radially opposite portions of the same beadseat portion 322 of rim 300. This bead seat diameter 328 may be greaterthan bead channel diameter 350. For example, for a nominal 29 inch rim,the bead channel diameter 350 may be approximately 551 millimeters whilethe bead seat portion diameter 328 may be approximately 559 millimeters.

Moreover, rim ledge 326 may have a diameter configured to both increasethe effectiveness of bead channel 310 in retaining the bead of anuninflated tire and easing the transition of the bead of the tire intobead seat portion 322 once a threshold pressure is established withinthe tire. Accordingly, in some embodiments the diameter of the rim ledge326 may be no greater than the diameter at laterally outward end 314 ofbead channel 310.

Specifically, in some embodiments, the laterally outward end 314 of thebead channel outer sidewall 312 may have a (radial) diameter that isgreater than the bead seat diameter 328. Thus, in such embodiments, rimledge 326 may include a surface that slopes substantially continuouslyfrom the outward end 314 of bead channel outer sidewall 312 to bead seatportion 322. This slope may be radially inward such that rim ledge 326may have a substantially decreasing radial diameter from outward end 314of bead channel outer sidewall 312 to bead seat portion 322. Forexample, the rim ledge 326 may have a negative angle relatively to thereference line parallel to the rim's radial (e.g., be greater than 90degrees from the normal axis) and in some embodiments may form an anglebetween 1 and 10 degrees with the radial axis.

Furthermore, the gradient of the slope may be substantially constantradially inward so that rim ledge 326 is a continuous straight slopedsurface from outward end 314 of bead channel outer sidewall 312 to beadseat portion 322. In other words, there may be no raised wall, bump,flange or other protuberance on rim ledge 326; outward end 314 of beadchannel 310 is of a greater radial diameter than any portion of rimledge 326 and no portion of rim ledge 326 is of a greater radialdiameter than the diameter of any portion of rim ledge 326 that islaterally inward of that portion. The slope of rim ledge 326 may serveto inhibit the escape or “burping” of air from the tire when lateralforces on the wheel or tire distort the tire.

Bead seat portion 322 may be adjacent to the base 384 of rim sidewall380 extending radially outward at the lateral ends of the supportportion 302. The transition between bead seat portion 322 and rimsidewall 380 may be curved to better maintain a seal between the bead ofan inflated tire and the inner surface of the rim 300. This curve may,in some embodiments, have a radius along the outer surface of the rim300 of approximately 3-5 mm, though other radii may be used. While insome embodiments radially outward end 386 or rim sidewall 380 may “hook”inwardly or have another inward protrusion such that the radiallyoutward end 386 may have at least a portion that is laterally inward ofthe base 384 of rim sidewall 380, in other embodiments, sidewall 380 maybe hookless and the radially outward end 386 of the rim sidewall may belaterally aligned with, or outward of, the base 384.

More particularly, in embodiments where the radially outward end 386 ofthe rim sidewall 380 is outward of base 384 the sidewall 380 may beoutwardly curved from base 384 to radially outward end 386 of thesidewall 380 such that radially outward end 386 is laterally outward ofthe radially inward base 384 of the sidewall 380. This curve may beradiused such that when the bead of an inflated tire is in bead seat 322the casing of the inflated tire contacts the sidewall 380 of the rim 300along at least portion of the curve of the sidewall 380. The contactbetween the tire casing and the sidewall 380 may serve to betterdistribute any stress from the tire casing throughout the sidewall 380and rim 300. By distributing stress in this manner, “burping” of airfrom the tire when lateral forces on the wheel or tire distort the tireand momentarily unseat the tire's bead from the rim 300 and cracking ofthe sidewall may be reduced. In some embodiments, this curve may have aradius on the outer surface of around 12-15 mm.

Rim 300 also includes a raised center bridge 370 extending between thebead channel inner sidewalls 318 of the bead channels 310. Morespecifically, center bridge 370 may be formed between laterally inwardends 374 of the bead channel inner sidewalls 318. The inner sidewall 318of the bead channels 310 may have a higher angle from the rim's radialaxis relative to outer sidewall 312. For example, this angle may bebetween 60-80 degrees (or between 10 and 30 degrees from the normalaxis). In one embodiment, the diameter of the rim at the laterallyoutward ends 372 of center bridge 370 adjacent to the laterally inwardends 374 of the inner sidewall 318 may be greater than all of the beadchannel diameter 350, the bead seat diameter 328 and the diameter of rimledge 326 at any point of rim ledge 326.

Embodiments of center bridge 370 may allow easier mounting of tire in anuninflated state while simultaneously serving to help control the beadsof the tire during inflation. Specifically, as in certain embodimentsthe center bridge 370 has a diameter at least at its laterally outwardends 372 that is greater than inward ends 374 of the inner sidewall 318,the center bridge 370 may serve to maintain a better seal between thesurface of the rim 300 before and during inflation of the tire, as beadsof the tire may be better prevented from deflecting toward thecenterline of the rim 300 and, as such deflection is better prevented,the beads of the tire are better directed to traveling laterally outwardon outer sidewall 312 while maintaining contact with the outer sidewall312.

In some embodiments, portions 382 of the raised center channel betweenthe laterally outward end 372 of the center bridge 370 and thecenterline of the rim 300 may be configured to more easily accommodatethe attachment of spokes to the support portion 302 of the rim. Forexample, portions 382 may slope radially inward from laterally outwardend 372 of the center bridge 370 toward the centerline. The angle ofthis slope may be a spoke angle such that when spokes are attached tothe portion 382 of the center bridge 370 the spokes may intersect theportion 382 at an angle close to, or substantially, perpendicular. Incertain embodiments, the angle between the portion 382 of the raisedcenter bridge 370 and the radial axis may be between 5 and 20 degrees(e.g., forming an angle of between 85 and 70 degrees with the normalaxis).

While a specific bead channel shape has been depicted with respect tothe embodiments as discussed above with respect to FIG. 3 other beadchannel and rim shapes may also be utilized in accordance withembodiments as disclosed herein. For example, FIG. 4 depicts across-sectional view of another embodiment of a bicycle rim 400 adaptedto seat a tire in a tubeless configuration. Rim 400 includes inwardprojections 402 at the outer ends of rim sidewalls 403. Rim 400 may beconfigured to be formed of aluminum. Also provided by way of example arethe following example dimensions: width 410 is 80 mm, width 412 is 36mm, width 414 is 4.9 mm, inward projections 402 project inwardly 0.85 mmfrom the inner surface of sidewalls 403 (indicated at 416), height 420is 8 mm, height 422 is 2.56 mm, height 424 is 5 mm, thickness 430 is2.56 mm, thickness 432 is 2.5 mm, thicknesses 433, 434 are 1.4 mm,thickness 436 is 1.2 mm, angle 440 is 5 degrees, angle 442 is 35degrees, angle 444 is 81 degrees. Dimensions provided are provided byway of example and other embodiments may be sized as needed or desired.

While embodiments as described above are formed of a single wall ofmaterial, other embodiments may also include an annular chamber wallthat forms a chamber between the center channel of the rim, or thesupport portion of the rim, and the chamber wall. This chamber wall may,for example, be curved about an axis parallel to the direction ofintended rotation of the rim. FIGS. 5A and 5B depict embodiments of arim with an annular support wall forming a chamber between it and themounting wall of the rim.

More specifically, FIG. 5A depicts an embodiment of a rim 600 includinga mounting wall 610 and an annular chamber wall 620 such that a chamber630 is formed between mounting wall 610 of the rim 600 and annularchamber wall 620. Mounting wall 610 may be a single wall of materialshaped according to embodiments as described above with respect to FIGS.2-4. Annular chamber wall 620 is a wall formed between the outer surfaceof distal ends of support portion 602 of mounting wall 610 and curvedabout an axis parallel to the direction of rotation of rim 600. Theradius of the curve of annular chamber wall 620 may be configured suchthat spokes of a wheel may be more easily and effectively attached andsecured through the annular chamber wall 620.

Similarly, FIG. 5B depicts an embodiment of a rim 650 including amounting wall 660 and an annular chamber wall 670 such that a chamber680 is formed between mounting wall 660 of the rim 650 and annularchamber wall 670. Mounting wall 660 may be a single wall of materialshaped according to embodiments as described above with respect to FIGS.2-4. Here, annular chamber wall 670 is a wall formed between the outersurface of bead channels 692 of mounting wall 660 and curved about anaxis parallel to the direction of rotation of the rim 650. Thus, in thisembodiment, the chamber 680 may be substantially between the annularchamber wall 670 and center channel 694 of mounting wall 660. Again, theradius of the curve of annular chamber wall 670 may be configured suchthat spokes of a wheel may be more easily and effectively attached andsecured through the annular chamber wall 670.

As rims shaped according to embodiments as described herein may providesignificant advantages, it may be desired to alter others rim shapessuch that they are shaped in accordance with the embodiments describedherein. In particular, it may be desired to alter conventional shapedtubeless rims similar to those described above with respect to FIGS. 1Aand 1B such that the resulting rim is shaped in accordance withembodiments as described. Referring back briefly to FIGS. 1A and 1B forcontext then, rim 100 includes a center channel 140 that issubstantially continuous between channel outer sidewalls 142 disposed oneither side of the centerline of the rim 100 at lateral ends of centerchannel 140. The radial diameter of the rim 100 increases from thebeginning of center channel outer sidewalls 142 to beginning of shelf180 in a direction away from the centerline of the rim 100 such that thebead seat diameter (i.e., the radial diameter of the rim at shelf 180proximate to sidewalls 170 where beads of the tire are seated in aninflated state) is greater than the center channel diameter.

Accordingly, then, such a rim does not have at least bead channelsdisposed across a centerline of a rim or a center bridge as may becharacteristic of certain embodiments as described herein. It maytherefore be desirable to modify rims of this type to include such beadchannels and a center bridge. To that end, embodiments may comprise arim strip including an annular piece of material such as plastic, metalor carbon that is formed separately from the rim and is configured to beattached to a rim (for example, along the centerline of the rim) so thatthe combination of the rim and the rim strip has a shape that includesbead channels and a raised center bridge as described above with respectto FIGS. 2-4.

Turning to FIGS. 6A and 6B one embodiment of such an annular rim stripis depicted. Rim strip 700 is configured to be attached to a rim 750.Rim strip 700 may be attached to rim 750 by, for example, adhering therim strip 700 to the rim 750 using an adhesive, forming the rim strip sothat it may be press fit into the center channel of the rim 750, using amechanical fastener such as a cable or zip tie generally aligned withthe centerline of the rim 750 to hold the rim strip 700 in place, or byanother suitable method.

Rim strip includes rim strip sidewalls 702 and a center section 710extending between the rim strip sidewalls 702. The rim strip sidewalls702 are spaced at less than a width of the center channel (e.g., betweenthe beginnings of the each channel outer sidewall 762) of the rim 750into which the rim strip 700 is to be fitted such that when the rimstrip 700 is attached to rim 750 two bead channels 752 are formed incooperation between rim strip (e.g., rim strip sidewalls 702) and theouter sidewalls 762 of the center channels of the rim 750. The centersection 710 extending between the rim strip sidewalls 702, whenattached, may also have a radial diameter greater than: the bead seatdiameter of the rim 750 to which it is attached, the laterally innermostportion of the tire shelf 760 of the rim 750, or all of the tire shelf760 of the rim 750. It may be realized that as long as bead channels areformed and the radial diameter of the rim strip 700 is as described whenthe rim strip is attached to a rim, substantially any shape desired maybe used for the rim strip 700 itself and that differently shaped rimstrips may be used with the same, or differently shaped, rims. Forexample, FIGS. 6C and 6D depict other shapes of a rim strip that may beformed according to embodiments as described herein. Other shapes forsuch a rim strip are also contemplated herein.

Thus, whether forming the rim itself into embodiments as described aboveor by attaching a separately formed rim strip to a conventional rim toproduce a rim with a shape as described above, a tire may be more easilymounted and inflated on such a rim. While it should be kept in mind thatembodiments of rims as described herein may be used in tubelessconfiguration or with a tube it may now be helpful to discuss how a tireis mounted on embodiments of such a rim in tubeless manner.

Broadly speaking, according to one embodiment, mounting the tire onembodiments of a rim such as those described above can comprise: 1)inserting the rim inside the tire so that the tire is “outside” of therim; 2) placing at least a first portion of a first bead of the tire ina bead channel of the rim so that it is captured by the bead channel; 3)placing at least a portion of the second bead of the tire in the otherbead channel of the rim so that it is captured by the other beadchannel; and 4) now that both tire beads are in the bead channelsinflating the tire so that the beads move up onto the tire ledges thathold the tire in place.

Referring now to FIGS. 7A and 7B, a cutaway partial view and a close-upcutaway partial view (A) of a tubeless tire and rim mounting interfaceaccording to one embodiment of a tubeless tire and rim is depicted. FIG.7C depicts the cutaway view of the rim with the tire after inflation.Initially, the rim 840 may be placed inside the tire 820 without a tubeand the beads 810 of the tire 820 may be positioned in bead channels 830in rim 840 shaped according to embodiments as described above.

To further aid in retaining the tire in the rim and in preventing airloss from the tire around the bead during inflation, embodiments mayutilize a mechanical seal between the tire bead and the bead channel.This mechanical seal 832 may be positioned in the bead channel 830 aspart of a manufacturing step or provided as part of a separate devicethat may be later installed. Mechanical seal 832 may be formed from acompressible material including elastomeric materials such as rubber,latex, silicone or the like. Such a mechanical seal may be a pre-formedgasket, such as an O-ring, band or other gasket. This mechanical seal832 may be sized to be in tension with the rim or bead channel 830 wheninstalled and may be disposed in one or both channels 830 about aportion of the circumference of the rim 840 or along an entirecircumference of the rim 840. This mechanical seal 832 may be positionedin channel 830 before a bead 810 is positioned in the bead channel 830or after the tire bead 810 is positioned in the bead channel 830.

In one embodiment, a mechanical seal for a rim having between a 26 inchand a 29 inch diameter may include an elastic ring, such as a rubberband, sized with an approximately 17 inch circumference, and having anon-circular cross section with a thickness of approximately 5-7 mm anda height of approximately 1 mm. However, those skilled in the art willappreciate that the size, cross-section shape, material, whether themechanical seal is installed during manufacturing or afterwards, orwhether the mechanical seal is used in both channels or a single channelmay vary according to the rim or tire being used or on a variety ofother factors.

For example, another type of mechanical seal that may be utilized is rimtape. This rim tape may be, for example, the same rim tape used inpreparing the rim 840 for the mounting of the tire. By using rim tape inthis manner a good seal between a tire and a rim 840 may be achieved toprevent or avoid air loss, flat tires, damage to a rim caused when atire is underinflated. Additionally, it may have the advantage ofallowing the mounting or dismounting of tires without tools. The rimtape may be applied around the circumference of the rim 840. Theapplication of the rim tape may also serve to seal the spoke nipples incases where the rim 840 does not include an airtight chamber such aswhen the rim 840 comprised of a single wall.

It will be apparent that multiple types of mechanical seals may be usedin conjunction with one another as well. For example, rim tape may beapplied around the circumference of the rim 840 and function as onemechanical seal and an elastomeric band may be placed within a beadchannel to function as an additional mechanical seal.

Returning to FIGS. 7A and 7B, regardless of whether a mechanical sealsuch an elastomeric band or rim tape is utilized, the first step inmounting the tire 820 in the rim 840 is to place or otherwise position abead 810 of the tire 820 into one of the bead channels 830, which alsomay be referred to as snapping the bead into the channel. For many tiresand rims, this step may be performed without tools. In otherembodiments, tools may be used.

At this point, if it is desired to use a separate mechanical seal in thebead channel such as an elastomeric ring, it may be placed into the beadchannel. Specifically, the bead 810 may be axially biased inward (e.g.,toward the centerline of the rim 840) to expose at least a portion ofthe bead channel 830. Once the bead channel 830 is exposed, themechanical seal 832 such as a rubber band, O-ring or other seal may bepositioned or applied in the bead channel. As discussed earlier, thismechanical seal will make it more difficult for the tire bead 810 tomove in the bead channel 830 and more difficult for air to escape oncethe tire is inflated. In some embodiments, a mechanical seal 832, whenpositioned, may be centered in the bead channel 830, does not cover anyportion of the tire ledge and may be positioned at least 1 mm below anytransition area of the bead channel 830 (e.g., a transition from theouter sidewall of the bead channel to the tire ledge or the innersidewall of the bead channel to the center bridge). Once the mechanicalseal 832 is positioned in the bead channel 830 (or portion of the beadchannel), the tire bead 810 (or portion of the tire bead) may bereleased or biased into the bead channel 830 and further in contact withthe mechanical seal.

Once a tire bead 810 is seated in a bead channel 830 (with or withoutuse of a mechanical seal 832), the process of mounting a tubeless tireonto rim 840 may proceed or may include performing similar steps tomount the second tire bead 810 into the second bead channel with orwithout a mechanical seal 832. Again, the bead, or a portion thereof,may be inserted or otherwise positioned into the bead channel (or aportion of the bead channel). At this point a mechanical seal 832 may bepositioned or applied in the channel if desired, substantially asdescribed above.

The portion of the second bead 810 that must be inserted into the secondbead channel 830 may vary based on the tire or rim. In some embodiments,75-80% of the second bead may be inserted into the second channel. As itmay be desired to use some form of tire sealant, this tire sealant canbe poured into the tire 820 at this point using gap left any portion ofthe tire bead out of the bead channel (e.g., 20-25%). The wheel may beshaken to distribute tire sealant throughout the tire. The amount oftire sealant needed will vary among different tire/rim combinations,sealant type and other factors. However, those skilled in the art willappreciate that embodiments disclosed herein may ensure a seal such thatair loss is prevented or greatly reduced using less (or no) sealant thanconventionally shaped rim.

Almost any method, either with or without or a tool may be used toinsert a bead 810 (or portion thereof) into a bead channel. For example,to insert a second bead 810 into a bead channel a person may lay the rimon its side (i.e., the side with the other bead already in the otherbead channel) and, without stepping on the rim 840, use his feet to snapthe second bead past the sidewall of the rim 840. Of course, any othersuitable method of inserting the second bead may also be used.

Once the beads 810 (or portions thereof) of the tire are in the beadchannels 830 the tire may be inflated in a tubeless manner. In manycases, a person will be able to simply inflate the tire 820 and the tirebeads 810 will gradually move onto the rim ledge, such that contactbetween the bead and the inner surface of the sidewall forms a seal toprevent air loss and any mechanical seal 832 is no longer needed. Infact, in many instances a person may able to inflate a tire in thismanner, on embodiments of rims as described, using only a hand pump.

When mounting the tire on such a rim, in certain cases, a bead mightresist properly seating on the rim ledge, and in these cases, water orsoap or the like may be used to help the tire bead(s) transition fromcontact with the bead channel (or mechanical seal(s) disposed therein)and onto the rim ledges. In certain scenarios, different tires or rimsmay still leak air. In these situations, a person may simply bias a beadaxially inward to expose the bead channel and any mechanical sealtherein, remove any existing mechanical seal and add a mechanical sealor different mechanical seal (i.e., a mechanical seal having a differentthickness, shape, size, etc.,) in lieu of the existing mechanical sealor add another mechanical seal in addition to the existing mechanicalseal, and repeat the steps of inflating the tire until the leaking hasstopped. The mechanical seal(s) may remain unseen in the bead channel(s)until the tire is removed.

Removal may be accomplished by substantially reversing the installationprocess. Thus, during removal, a person may fully deflate the tire,knock both beads of the tier into their respective channels, remove anymechanical seals found in the bead channels, and then remove the tires,which may be accomplished easily using a tire lever.

Although specific embodiments have been described, these embodiments aremerely illustrative, and not restrictive of the invention. Thedescription herein of illustrated embodiments of the invention is notintended to be exhaustive or to limit the invention to the precise formsdisclosed herein (and in particular, the inclusion of any particularembodiment, feature or function within the Abstract or Summary is notintended to limit the scope of the invention to such embodiment, featureor function). Rather, the description is intended to describeillustrative embodiments, features and functions in order to provide aperson of ordinary skill in the art context to understand the inventionwithout limiting the invention to any particularly described embodiment,feature or function, including any such embodiment feature or functiondescribed in the Abstract or Summary. While specific embodiments of, andexamples for, the invention are described herein for illustrativepurposes only, various equivalent modifications are possible within thespirit and scope of the invention, as those skilled in the relevant artwill recognize and appreciate. As indicated, these modifications may bemade to the invention in light of the foregoing description ofillustrated embodiments of the invention and are to be included withinthe spirit and scope of the invention. Thus, while the invention hasbeen described herein with reference to particular embodiments thereof,a latitude of modification, various changes and substitutions areintended in the foregoing disclosures, and it will be appreciated thatin some instances some features of embodiments of the invention will beemployed without a corresponding use of other features without departingfrom the scope and spirit of the invention as set forth.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,product, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, product,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

Reference throughout this specification to “one embodiment”, “anembodiment”, or “a specific embodiment” or similar terminology meansthat a particular feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodimentand may not necessarily be present in all embodiments. Thus, respectiveappearances of the phrases “in one embodiment”, “in an embodiment”, or“in a specific embodiment” or similar terminology in various placesthroughout this specification are not necessarily referring to the sameembodiment. Furthermore, the particular features, structures, orcharacteristics of any particular embodiment may be combined in anysuitable manner with one or more other embodiments. It is to beunderstood that other variations and modifications of the embodimentsdescribed and illustrated herein are possible in light of the teachingsherein and are to be considered as part of the spirit and scope of theinvention.

In the description herein, numerous specific details are provided, suchas examples of components and/or methods, to provide a thoroughunderstanding of embodiments of the invention. One skilled in therelevant art will recognize, however, that an embodiment may be able tobe practiced without one or more of the specific details, or with otherapparatus, systems, assemblies, methods, components, materials, parts,and/or the like. In other instances, well-known structures, components,systems, materials, or operations are not specifically shown ordescribed in detail to avoid obscuring aspects of embodiments of theinvention. While the invention may be illustrated by using a particularembodiment, this is not and does not limit the invention to anyparticular embodiment and a person of ordinary skill in the art willrecognize that additional embodiments are readily understandable and area part of this invention. Any dimensions provided are provided by way ofexample and other embodiments may be sized as needed or desired.

It will also be appreciated that one or more of the elements depicted inthe drawings/figures can also be implemented in a more separated orintegrated manner, or even removed or rendered as inoperable in certaincases, as is useful in accordance with a particular application.Additionally, any signal arrows in the drawings/figures should beconsidered only as exemplary, and not limiting, unless otherwisespecifically noted.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any component(s) thatmay cause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature or component.

What is claimed is:
 1. A bicycle rim adapted to seat a tubeless and tubetires, comprising: an annular support portion forming a continuous ringhaving an outer tire mounting surface and further comprising: a taperedfirst bead channel having a bead channel diameter disposed to a firstside of a centerline of the support portion, further comprising: a firstbead channel outer sidewall sloped such that a radially outer end of thefirst bead channel outer sidewall is laterally outward of a radiallyinner end of the first bead channel outer sidewall; a first bead channelinner sidewall; a tapered second bead channel having the bead channeldiameter disposed to a second side of the centerline, furthercomprising: a second bead channel outer sidewall sloped such that aradially outer end of the second bead channel outer sidewall islaterally outward of a radially inner end of the second bead channelouter sidewall; a second bead channel inner sidewall; a first bead seatportion and a second bead seat portion, the first bead seat portiondisposed laterally outward of the first bead channel from the centerlineand the second bead seat portion disposed laterally outward of thesecond bead channel from the centerline, the first bead seat portion andsecond bead seat portion having a bead seat diameter that is greaterthan the bead channel diameter; a first rim ledge extending from thefirst bead channel outer sidewall to the first bead seat portion and asecond rim ledge extending from the second bead channel outer sidewallto the second bead seat portion, wherein the outer tire mounting surfaceis free of sharp corners between the first bead channel and the firstbead seat portion and between the second bead channel and the secondbead seat portion; a center bridge extending from the first bead channelinner sidewall to the second bead channel inner sidewall, wherein thecenter bridge has a diameter at a first lateral end and a second lateralend of the center bridge that is greater than the bead channel diameter,bead seat diameter and diameters of the first rim ledge and second rimledge; and a first rim sidewall and a second rim sidewall extendingradially outward from the support portion.
 2. The bicycle rim of claim1, wherein a bottom of the first bead channel comprises a continuousinside curve between the first bead channel inner sidewall and the firstbead channel outer sidewall and a bottom of the second bead channelcomprises a continuous inside curve between the second bead channelinner sidewall and the second bead channel outer sidewall.
 3. Thebicycle rim of claim 1, wherein the first rim ledge is sloped radiallyinward from a transition to the first bead channel outer sidewall to thefirst bead seat portion and the second rim ledge is sloped radiallyinward from a transition to the second bead channel outer sidewall tothe second bead seat portion.
 4. The bicycle rim of claim 3, wherein thefirst rim ledge comprises a continuous straight sloped outer surfacefrom the transition to the first bead channel outer sidewall to thefirst bead seat portion and the second rim ledge comprises a continuousstraight sloped outer surface from the transition to the second beadchannel outer sidewall to the second bead seat portion.
 5. The bicyclerim of claim 1, wherein the center bridge comprises a first portion tothe first side of the centerline sloped at a spoke angle and a secondportion to the second side of the centerline sloped at the spoke angle.6. The bicycle rim of claim 1, wherein the first and second rimsidewalls are hookless.
 7. The bicycle rim of claim 6, wherein the firstand second rim sidewalls curve outward so that radially outward ends ofthe first and second rim sidewalls are laterally outward of radiallyinward ends of the first and second rim sidewalls.
 8. The bicycle rim ofclaim 1, wherein the first and second rim sidewalls curve outward with acurve selected so that a tire casing of an inflated tire contacts thefirst and second rim sidewalls along an inner side of the curve todistribute stress.
 9. The bicycle rim of claim 1, further comprising anannular mechanical seal disposed along a bottom of the first beadchannel or the second bead channel.
 10. The bicycle rim of claim 1,wherein a transition between the first bead channel outer sidewall andthe first rim ledge and a transition between the second bead channelouter sidewall and second rim ledge are outer curves configured toprevent gapping between a tire bead and the support portion as the tirebead transitions from the first or second bead channel to the first orsecond rim ledge.
 11. The bicycle rim of claim 1, wherein the bicyclerim is formed as a single wall.
 12. The bicycle rim of claim 11,wherein: a bottom of the first bead channel comprises a continuousinside curve between the first bead channel inner sidewall and the firstbead channel outer sidewall and a bottom of the second bead channelcomprises a continuous inside curve between the second bead channelinner sidewall and the second bead channel outer sidewall; the first rimledge is sloped radially inward from a transition to the first beadchannel outer sidewall to the first bead seat portion and the second rimledge is sloped radially inward from a transition to the second beadchannel outer sidewall to the second bead seat portion; a transitionbetween the first bead channel outer sidewall and the first rim ledgeand a transition between the second bead channel outer sidewall and thesecond rim ledge are outer curves configured to prevent gapping betweena tire bead and the support portion as the tire bead transitions fromthe first or second bead channel to the first or second rim ledge;wherein the first and second rim sidewalls curve outward so thatradially outward ends of the first and second rim sidewalls arelaterally outward of radially inward ends of the first and second rimsidewalls; and the center bridge comprises a first portion to the firstside of the centerline sloped at a spoke angle and a second portion tothe second side of the centerline sloped at the spoke angle.
 13. Thebicycle rim of claim 1, wherein the annular support portion furthercomprises an annular chamber wall chamber wall forming a chamber betweenthe center bridge and the chamber wall, the chamber wall curved about anaxis parallel to direction of rotation of the bicycle rim.
 14. Thebicycle rim of claim 1, wherein the first rim ledge comprises acontinuous straight outer surface from a transition to the first beadchannel outer sidewall to the first bead seat portion that does notincrease in diameter from the transition to the first bead channel outersidewall to the first bead seat portion and the second rim ledgecomprises a continuous straight outer surface from a transition to thesecond bead channel outer sidewall to the second bead seat portion thatdoes not increase in diameter from the transition to the second beadchannel outer sidewall to the second bead seat portion.
 15. A method formounting a tubeless tire, comprising: placing a bicycle rim having anannular support portion with an outer tire mounting surface between afirst tire bead and a second tire bead of a tire; placing the first tirebead in a tapered first bead channel having first bead channel outersidewall that is sloped such that a radially outer end of the first beadchannel outer sidewall is laterally outward of a radially inner end ofthe first bead channel outer sidewall, the first bead channel disposedto a first side of a centerline of the rim; placing the second tire beadin a tapered second bead channel having a second bead channel outersidewall that is sloped such that a radially outer end of the secondbead channel outer sidewall is laterally outward of a radially inner endof the second bead channel outer sidewall; maintaining a separationbetween the first tire bead and the second tire bead with a centerbridge of the bicycle rim, the center bridge extending from a first beadchannel inner sidewall to a second bead channel inner sidewall whereinthe center bridge has a center bridge diameter at a first lateral endand a second lateral end of the center bridge; and inflating the tire tocause the first tire bead to transition along the outer tire mountingsurface from the first bead channel and across a first rim ledge to afirst bead seat portion disposed laterally outward of the first beadchannel such that the tire contacts a first rim sidewall that extendsradially outward from the support portion and to cause the second tirebead to transition along the outer tire mounting surface from the secondbead channel and over a second rim ledge to a second bead seat portiondisposed laterally outward of the second bead channel such that the tirecontacts a second rim sidewall that extends radially outward from thesupport portion, wherein the outer tire mounting surface is free ofsharp corners between the first bead channel and the first bead seatportion and between the second bead channel and the second bead seatportion and wherein the first bead seat portion and second bead seatportion have a bead seat diameter that is greater than a bead channeldiameter and less than the center bridge diameter.
 16. The method ofclaim 15, further comprising placing a first mechanical seal in thefirst bead channel such that the first mechanical seal covers a portionof the first bead channel outer sidewall, wherein placing the first tirebead in the first bead channel comprises placing the first tire bead incontact with the second mechanical seal.
 17. The method of claim 16,wherein the first mechanical seal comprises an elastic ring.
 18. Themethod of claim 16, wherein the first mechanical seal comprises rimtape.
 19. The method of claim 16, further comprising placing a secondmechanical seal in the second bead channel such that the secondmechanical seal covers a portion of the second bead channel outersidewall, wherein placing the second tire bead in the second beadchannel comprises placing the second tire bead in contact with thesecond mechanical seal.
 20. The method of claim 19, wherein the firstmechanical seal comprises a first elastic ring and the second mechanicalseals comprise a second elastic ring.
 21. The method of claim 19,wherein the first and second mechanical seals comprise rim tape.